Cerebral edema is a type of brain swelling most commonly associated with cerebral trauma or mass lesions, which results in an increase in volume of intracranial contents leading to serious, and sometimes fatal, intracranial pressure. Interstitial (extracellular) fluid, or free water, is abnormal in the brain and accumulates as a result of swelling from a nearby brain tumor, or other type of cerebral lesion. This fluid enters the white matter in the brain due to a compromise of the blood-brain barrier. The fluid can contain small proteins, as well as other small molecular weight molecules, which escape the circulatory system or are a result from the tissue damage itself.
Currently, there is no known approach for removing or draining interstitial fluid from a cerebral edema. Methods exist only for improving the symptoms of swelling due to the accumulation of the fluid. These methods involve the use of oral or intravenous steroids, which have known systemic side effects. For example, the steroid DECADRON.TM. has only a modest effect on cerebral edema and has systemic side effects including water retention, osteoporosis, aseptic necrosis of the femoral head, capillary fragility with easy bruising, increased appetite, and insomnia.
Prior art fluid draining systems only teach removing cerebrospinal fluid, and other fluids, from 5 ventricles in the brain. These draining systems consist of a shunt which protrudes into the ventricular region, such as a typical catheter described in U.S. Pat. NO. 4,215,695, issued to Spitz, et al. In such prior art catheters, the pressure of the cranial cavity serves as the mechanism which moves the cerebrospinal fluid through the catheter to an extracorporeal collection area or other region within the patient's body for disposal. However, sufficient pressure is not present in the region of a cerebral edema to provide for this type of mechanism for transporting interstitial fluid through a ventricle type shunt placed in the region.
Accordingly, a need exists for such an apparatus for draining interstitial fluid from a cerebral edema. The cerebral edema catheter described below provides for the drainage of interstitial fluid from a cerebral edema.